This invention relates to a heat engine.
The heat engine is an alternate engine to the internal combustion engine. Various designs for heat engines have been developed in the past. Despite its potential for greater thermodynamic efficiency compared to internal combustion engines, heat engines have been used in only limited applications in the past due to several factors including the complexity of the designs, the weight of the engine per unit of horse power output as well as the difficulty in starting a heat engine.
In accordance with the instant invention, an improved design for a heat engine is disclosed. In one embodiment, the heat engine is made from lightweight sheet metal. By using a plurality of cylindrical containers, one nested inside the other for the displacer, the combustion and cooling chambers as well as to create an air flow path between the heating and cooling chambers, a rugged durable lightweight construction is achieved.
In another embodiment, the heat engine utilizes a power piston which is biased to a first position. By biasing the piston, several advantages are obtained. First, the heat engine may be self starting provided the power piston is biased so as to be initially positioned in the cooling chamber. A further advantage is that by using an electrical means (eg. a solenoid, an electromagnet or the like) to move the displacer, preferably in response to the position of the power piston, a complicated mechanical linkage between the power piston and the displacer is not required thus simplifying the design. Further, by using an electrical linkage, the phase angle between the displacer and the power piston may be adjusted.
The heat engine of the instant invention may be combined with a fuel source (eg. butane), a linear generator and an electrically operated light emitting means to create a flashlight or other portable light source. It will be appreciated that due to the simplicity of the design of the instant invention, the heat engine as well as the linear generator are each adapted to be scaled up or down so as to produce greater or lessor amounts of power. Accordingly, in another embodiment, the heat engine together with a linear generator and a fuel source may be used as a generator. It will further be appreciated that by connecting a linear generator to a source of electricity (eg. standard electrical outlet) the electricity from a power grid may be used to run the linear generator as a motor whereby the power piston effectively drives the displacer. In such a case, the heat engine may be used as a refrigerator or a cryogenic cooler. In such an embodiment, the heating and cooling chambers of the heat engine are effectively reversed and no combustion chamber is required.
In accordance with one aspect of the instant invention, there is provided a heat engine comprising inner and outer spaced apart longitudinally extending walls, each wall having an inner surface and an outer surface, the inner wall surrounding a cavity, each of the inner and outer wall having longitudinally spaced apart first and second ends, the first end is at a different temperature than the second end when the heat engine is in use, the first and second ends in fluid flow communication via a passageway, the first and second ends and the passageway defining a sealed region; and, a heat exchanger mounted on a portion of one of the walls, the heat exchanger comprising at least one fin extending around the portion of the wall and having first and second opposed sides and a plurality of main the fin. Alternately, at least one of the main directing members preferably has a first side, a second side and at least one associated secondary directing member, the secondary directing member is configured and arranged to cause the fluid to flow unidirectionally from one side of a main directing member with which the secondary directing member is associated to the other side as the fluid flows through the fin.
In another embodiment, the fin comprises a hub and a main body portion extending away from the hub, and the main directing members comprise flanges extending away from an opening in the main body portion.
In another embodiment, the fin comprises a hub and a main body portion extending away from the hub, the main body portion having a plurality of openings, and the main directing members comprise louvres extending away from an opening in the main body portion and in contact with the main body portion at a plurality of positions which are nonlinear.
In another embodiment, the fin comprises a hub and a main body portion extending away from the hub, and the main directing members comprises a plurality of blades extending away from the hub.
In another embodiment, the fin is constructed from metal and is prepared by stamping.
In another embodiment, each annular fin has a deformable collar for lockingly engaging a wall.
In another embodiment, the fin is mechanically affixed to the wall by a pressure which is exerted between the fin and the wall which is sufficient to ensure that the rate of heat transfer between the wall and the fin is maintained over the normal operating temperature of the wall. directing members, the fin configured and arranged to produce a main flow of fluid which flows through the fin and to produce a secondary fluid flow which passes through the main directing members whereby the heat transfer between the fluid and the heat exchanger is enhanced.
In one embodiment, the at least one fin comprises a plurality of individual longitudinally spaced apart annular fins.
In another embodiment, the at least one fin comprises a helical fin.
In another embodiment, the main directing members are configured and arranged to direct a portion of the fluid which passes from the first opposed side to the second opposed side to subsequently flow from the second opposed side to the first opposed side as the fluid flows longitudinally through the heat exchanger. Preferably, at least one of the main directing members has associated secondary directing members, the secondary directing members are configured and arranged to cause a portion of the fluid to pass at least twice through the main directing member with which the secondary directing members are associated as the fluid flows through the fin. Alternately, at least one of the main directing members preferably has a first side, a second side and at least one associated secondary directing member, the secondary directing member is configured and arranged to cause the fluid to flow unidirectionally from one side of a main directing member with which the secondary directing member is associated to the other side as the fluid flows through the fin.
In another embodiment, the main directing members are configured and arranged to cause fluid to flow rotationally through the heat exchanger. Preferably, at least one of the main directing members has associated secondary directing members, the secondary directing members are configured and arranged to cause a portion of the fluid to pass at least twice through the main directing member with which the secondary directing members are associated as the fluid flows through In accordance with another aspect of the instant invention, there is provided a heat exchanger capable of being mounted in an fluid flow passage which is located between first and second walls, the walls having a first end and a spaced apart second end, the heat exchanger comprising at least one fin extending between the first and second walls, the at least one fin having first and second opposed sides and a plurality of main directing members, the at least one fin configured and arranged to produce a main flow of fluid which flows through the at least one fin as the fluid flows through the passage from the first end to the second end and to produce a secondary fluid flow which passes through the main directing members whereby the heat transfer between the fluid and the at least one fin is enhanced.
In one embodiment, the at least one fin comprises a plurality of individual longitudinally spaced apart annular fins.
In another embodiment, the at least one fin comprises a helical fin.
In another embodiment, the main directing members are configured and arranged to direct a portion of the fluid which passes from the first opposed side to the second opposed side to subsequently flow from the second opposed side to the first opposed side as the fluid flows longitudinally through the heat exchanger. Preferably, at least one of the main directing members has associated secondary directing members, the secondary directing members are configured and arranged to cause a portion of the fluid to pass at least twice through the main directing member with which the secondary directing members are associated as the fluid flows through the fin. Alternately, at least one of the main directing members preferably has a first side, a second side and at least one associated secondary directing member, the secondary directing member is configured and arranged to cause the fluid to flow unidirectionally from one side of a main directing member with which the secondary directing member is associated to the other side as the fluid flows through the fin.
In another embodiment, the main directing members are configured and arranged to cause fluid to rotate as it flows through the heat exchanger. Preferably, at least one of the main directing members has associated secondary directing members, the secondary directing members are configured and arranged to cause a portion of the fluid to pass at least twice through the main directing member with which the secondary directing members are associated as the fluid flows through the fin. Alternately, at least one of the main directing members preferably has a first side, a second side and at least one associated secondary directing member, the secondary directing member is configured and arranged to cause the fluid to flow unidirectionally from one side of a main directing member with which the secondary directing member is associated to the other side as the fluid flows through the fin.
In another embodiment, the at least one fin comprises a hub and an annular main body portion extending away from the hub, and each main directing member comprises a flange extending away from an opening in the main body portion.
In another embodiment, the at least one fin comprises a hub and an annular main body portion extending away from the hub, and each main directing member comprises a portion stamped from the main body portion and extending away from an opening in the main body portion and affixed to the main body portion at a plurality of positions which are nonlinear.
In another embodiment, the at least one fin comprises a hub and an annular main body portion extending away from the hub, and the main directing members comprise a plurality of blades extending radially away from the hub.
In another embodiment, each fin is constructed from metal and is prepared by stamping.
In another embodiment, each fin has a deformable collar for lockingly engaging a wall.
In another embodiment, the fin is mechanically affixed to the wall by a pressure which is exerted between the fin and the wall which is sufficient to ensure that the rate of heat transfer between the wall and the fin is maintained over the normal operating temperature of the wall.
In accordance with another aspect of the instant invention, there is provided a heat engine comprising outer container means having an outer surface; inner container means having a longitudinally extending axis and positioned inside the outer container means, the inner container means having first and second longitudinally spaced apart ends; fluid conduit means for connecting the first and second ends in fluid flow communication; and, heat exchanger means mounted on at least one of the container means and having fin means and a first end and a second end, the fin means having first and second opposed sides and first directing means for generating a main flow of fluid through the fin means as the fluid flows from the first end to the second end and secondary directing means for generating a secondary fluid flow which passes through at least some of the first directing means whereby the heat transfer between the fluid and the heat exchanger means is enhanced.
In one embodiment, the first directing means generates an axial flow of fluid through the heat exchanger means.
In another embodiment, the first directing means generates a rotational flow of fluid through the heat exchanger means.
In another embodiment, at least some of the first directing means direct the fluid from the first opposed side to the second opposed side and from the second opposed side to the first opposed side.
In another embodiment, the fin means have mounting means for press fitting the fin means on the container means.
In another embodiment, the secondary directing means are configured and arranged to cause a portion of the fluid to pass at least twice through the first directing means with which the secondary directing means are associated as the fluid flows through the fin means.
In another embodiment, the main directing means has a first side, a second side, the secondary directing means is configured and arranged to cause the fluid to flow unidirectionally from one side of a main directing means with which the secondary directing means is associated to the other side as the fluid flows through the fin means.
In accordance with another aspect of the instant invention, there is provided a heat exchanger means capable of being mounted in an fluid flow passage which is located between first and second walls, the walls having a first end and a spaced apart second end, the heat exchanger means comprising fin means having first and second opposed sides and first directing means for generating a main flow of fluid through the fin means as the fluid flows from the first end to the second end and secondary directing means for generating a secondary fluid flow which passes through at least some of the first directing means whereby the heat transfer between the fluid and the heat exchanger means is enhanced.
In one embodiment, the first directing means generates an axial flow of fluid through the heat exchanger means.
In another embodiment, the first directing mean generates a rotational flow of fluid through the heat exchanger means.
In another embodiment, at least some of the first directing means direct the fluid from the first opposed side to the second opposed side and from the second opposed side to the first opposed side.
In another embodiment, the fin means have mounting means for press fitting the fin means on the container means.
In another embodiment, the fin means comprises a plurality of individual longitudinally spaced apart annular fins.
In another embodiment, the fin means comprises a helical fin.
In another embodiment, the fin means is mechanically affixed to the wall by a pressure which is exerted between the fin means and the wall which is sufficient to ensure that the rate of heat transfer between the wall and the fin means is maintained over the normal operating temperature of the wall.
In another embodiment, the secondary directing means are configured and arranged to cause a portion of the fluid to pass at least twice through the first directing means with which the secondary directing means are associated as the fluid flows through the fin means.
In another embodiment, the main directing means has a first side, a second side, the secondary directing means is configured and arranged to cause the fluid to flow unidirectionally from one side of a main directing means with which the secondary directing means is associated to the other side as the fluid flows through the fin means.